SANAA, Yemen - A Yemeni security official says gunmen have blown up a voting station in the southern city of Aden one day before the country is to go to the polls to rubber stamp the vice-president as the new head of state.

The official said the gunmen fired a rocket-propelled grenade at the station on Monday, then fled. No one was hurt, and police are searching for suspects, the official said, speaking on condition of anonymity under security protocol.

The attack underlines the security vacuum in Yemen after a one-year-old popular uprising seeking to oust longtime President Ali Abdullah Saleh. Under a U.S.-backed deal brokered by Yemen's Arab Gulf neighbours, Saleh's deputy, Abed Rabbo Mansour Hadi, is to become president after elections Tuesday in which he is the only candidate.